Emerging Energy Research (EER), a renewable energy advisory firm based in Cambridge, Mass., recently profiled nine of the largest transmission initiatives under development in the western U.S., which are set to unlock 57 GW of new wind power - more than tripling the existing wind power capacity in the country.

While most of these large-scale projects are not scheduled for completion until after 2015, hundreds of smaller transmission lines and grid upgrades can provide a more immediate impact on wind power development in the U.S., according to the research.

The nine projects analyzed by EER could open up large regions of wind resources stretching from Minnesota to Southern California. In some regional transmission areas, such as the Midwest Independent Transmission System Operator and Southwest Power Pool, EER found that wind projects are the most proposed form of generation, comprising an average of 80% of the total generation seeking to interconnect.

Wind development activity across the U.S. has prompted some planners to reshape transmission projects to include wind: At least four of transmission projects profiled by EER were initially targeted for coal generation and have been adapted to address booming demand for wind power in the western U.S.

The U.S. wind power industry finished 2008 at a record pace, just ahead of EER's 2008 base case forecast of 8,203 MW. EER's high-growth wind power forecast - which factors in a national renewable portfolio standard and stepped up investment in transmission - estimates 187 GW of wind power capacity by 2020, accounting for nearly 14% of total U.S. power consumption.

But wind development in the U.S. remains constrained by an inadequate and aging transmission infrastructure that hampers the delivery of wind-generated power from regions of wind-rich resource to population centers with growing clean energy demands. None of the nine projects profiled by EER are expected to be fully operational before 2013, and the time frame for new grid capacity is made even more uncertain as these large projects face complex permitting and siting hurdles.

"The inability of transmission build-out to keep pace with wind project development activity will increasingly constrain the growth of the U.S. wind power market in the near term," according to Matthew Kaplan, senior wind analyst at EER.

With none of the large-scale transmission initiatives expected to come online between now and 2012, annual growth in the U.S. wind market may stall at 8 GW to 9 GW per year, according to EER.